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Rapid automatic segmentation and visualization of teeth in CT-scan data

Journal of Applied sciences 2009年第11期9卷 2031-2044页

作者： Akhoondali, H. Zoroofi, R.A. Shirani, G. Control and Intelligent Processing Center of Excellence Faculty of Engineering School of Electrical and Computer Engineering University of Tehran Tehran Iran Department of Oral and Maxillofacial Surgery Faculty of Dentistry Medical Science University of Tehran Tehran Iran

In this study, a fast automatic method is proposed for the segmentation and visualization of teeth in multi-slice CT-scan data of the head. The algorithm consists of five main procedures. In the first part, the mandible and maxilla are separated using maximum intensity projection in the y direction and a step like region separation algorithm. In the second part, the dental region is separated using maximum intensity projection in the z direction, thresholding and cropping. In the third part, the teeth are rapidly segmented using a region growing algorithm based on four thresholds which are used to distinguish between seed points, teeth and none teeth tissue. In the fourth part, the results are visualized using iso-surface extraction and surface and volume rendering. A semi-automatic method is also proposed for rapid metal artifact removal. Results on multiple dadasets have shown the success of the algorithm with the dental region separation and segmentation procedure taking an average of only 2.4 sec to complete for each jaw making it at least tens of times faster than any previously proposed method. © 2009 Asian Network for Scientific Information.

关键词： computerized tomography

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Fully automatic extraction of panoramic dental images from CT-scan volumetric data of the head

引用

Journal of Applied sciences 2009年第11期9卷 2106-2114页

In this study, a fully automatic technique is proposed for the extraction of panoramic dental images from CT-scan images of the teeth. The process is performed in three steps: Mandibular region isolation, mandibular curve creation and panoramic image extraction. First the mandibular region is isolated. To do this the maxilla and mandible are separated from each other by finding the slice separating them. Then an image of the maximum intensity projection of the slices containing the mandible is obtained. The projection of the mandible is then isolated from the other bones. Using the isolated mandible region an initial curve is created. Nine control points are then selected on the curve. These control points are used to create a fine curve using cubic splines. The formula for each spline segment is used to find the perpendicular lines to the spline on each point on the spline. These perpendicular lines are then used in all slices (mandible and maxilla) to create the panoramic images. The algorithm has many advantages over earlier methods. Results using multiple datasets have shown that the algorithm is robust. © 2009 Asian Network for Scientific Information.

关键词： computerized tomography

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Optimal design of oversampled filter banks with lattice structure

Optimal design of oversampled filter banks with lattice stru...

引用

Asian control Conference

作者： Li Chai Jingxin Zhang Yuxia Sheng Measurement Technology and the Key Laboratory of Metallurgical Equipment and Control Wuhan University of Science and Technology Wuhan China Department of Electrical and Computer Systems Engineering Monash University Clayton VIC Australia

ISBN: (纸本)9781424454402

For an oversampled linear phase (LP) perfect reconstruction filter banks with lattice structure, the synthesis FB is not unique. However, existing methods to choose a synthesis FB for ldquooptimalrdquo noise reduction may destroy the linear phase and lattice structure property. This paper studies the noise reduction design problem for oversampled filter banks (FBs) preserving lattice structure. Both the optimal design and worst case design are considered, where the former caters for the noise with known power spectral density (PSD), and the latter for the noise with unknown PSD. Explicit formula for the former and LMI-based algorithms for the latter are provided.

关键词： Filter bank Lattices Noise reduction Image reconstruction Signal synthesis Image processing Nonlinear filters Optimal control Quantization Noise robustness

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Polynomial kernel function and its application in locally polynomial neurofuzzy models

Polynomial kernel function and its application in locally po...

引用

International CSI computer Conference, CSICC

作者： A. Shirvani H. Chegini S. Setayeshi C. Lucas Tehran Science and Research Branch Computer Engineering Department Islamic Azad University Iran Faculty of Nuclear Engineering and Physics Amirkabir University of Technology슠 Tehran Iran Electrical and Computer Engineering Department Control and Intelligent Processing Center of Excellence University of Tehran Tehran Iran

Polynomials are one of the most powerful functions that have been used in many fields of mathematics such as curve fitting and regression. Low order polynomials are desired for their smoothness, good local approximation and interpolation. Being smooth, they can be used to locally approximate almost any derivable function. This means that when linear functions fail in approximation (e.g. where the first order Taylor expansion equals zero) polynomial functions can be used in local approximation, such that one can achieve better estimations at extremums. In this paper, application of polynomial kernel functions in locally linear neurofuzzy models is shown. Using polynomial kernels in local models, better local approximations in prediction of chaotic time series such as Mackey-Glass is achieved, and the capability of the neurofuzzy network is enhanced.

关键词： Polynomials Kernel Neurons Predictive models Power engineering and energy Chaos Application software Physics computing Power engineering computing Taylor series

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Optimization of maintenance for power system equipment using a predictive health model

Optimization of maintenance for power system equipment using...

引用

Power Tech Conference

作者： G. Bajracharya T. Koltunowicz R. R. Negenborn Z. Papp D. Djairam B. De Schutter J. J. Smit Faculty of Electrical Engineering Mathematics and Computer Science Department High-voltage Components and Power Systems Delft University of Technnology Delft Netherlands Delft Center of Systems and Control Delft University of Technnology Delft Netherlands TNO Science and Industry Delft Netherlands Faculty of Electrical Engineering Mathematics and Computer Science Department High-voltage Components and Power Systems Transport Technology Department Delft University of Technnology Delft Netherlands

In this paper, a model-predictive control based framework is proposed for modeling and optimization of the health state of power system equipment. In the framework, a predictive health model is proposed that predicts the health state of the equipment based on its usage and maintenance actions. Based on the health state, the failure rate of the equipment can be estimated. We propose to use this predictive health model to predict the effects of different maintenance actions. The effects of maintenance actions over a future time window are evaluated by a cost function. The maintenance actions are optimized using this cost function. The proposed framework is applied in the optimization of the loading of transformers based on the thermal degradation of the paper insulation.

关键词： Power system modeling Predictive models Aging Cost function Marine technology Power transformer insulation Predictive maintenance Power system management Investments Power system reliability

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∞ model reduction for linear parameter-varying systems with distributed delay

引用

International Journal of control 2009年第3期82卷 408-422页

作者： Ligang Wu Peng Shi Huijun Gao & Junling Wang Space Control and Inertial Technology Research Center Harbin Institute of Technology Harbin 150001 P. R. China Faculty of Advanced Technology University of Glamorgan Pontypridd CF3 1DL UK Department of Electrical and Computer Engineering University of Alberta Edmonton Alberta Canada College of Nuclear Science and Technology Harbin Engineering University Nantong Street 145 Harbin 150001 China

This paper is concerned with the ∞ model reduction for linear parameter-varying (LPV) systems with both discrete and distributed delays. For a given stable system, our attention is focused on the construction of reduced-order models, which approximate the original system well in an ∞ norm sense. First, a sufficient condition is proposed for the asymptotic stability with an ∞ performance of the error system by using the parameter-dependent Lyapunov functional method. Then, the decoupling technique is applied, such that there does not exist any product term between the Lyapunov matrices and the system matrices in the parametrised linear matrix inequality (PLMI) constraints; thus a new sufficient condition is obtained. Based on the new condition, two different approaches are developed to solve the model reduction problem. One is the convex linearisation approach and the other is the projection approach. Finally, a numerical example is provided to demonstrate the effectiveness of the proposed design method

关键词： Distributed delay model reduction parameterised linear matrix inequality (PLMI) linear parameter-varying (LPV) systems

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Simulation of light scattering from nanostructured surfaces

引用

Key engineering Materials 2008年 381-382卷 27-30页

作者： Tausendfreund, A. Patzelt, S. Simon, S. Goch, G. University of Bremen Faculty of Production Engineering Department of Measurement and Control Badgasteiner Straße 1 28359 Bremen Germany Hochschule Bremen Department of Electrical Engineering and Computer Engineering Flughafenallee 10 28199 Bremen Germany

This paper presents an efficient computation method to evaluate scattered light intensity distributions, generated by a nanostructured surface which is illuminated with a monochromatic laser beam of several millimeters in diameter. The new simulation approach based on a modified Huygens-Fresnel approximation enables to improve measuring methods without expensive and time consuming experiments. The qualitative verification of the model results in a roughness measuring principle based on double scattering of coherent light.

关键词： Light scattering

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Pole-zero cancellation circuit with pulse pile-up tracking system for low noise charge-sensitive amplifiers

Pole-zero cancellation circuit with pulse pile-up tracking s...

引用

作者： Grybos, Pawel Szczygiel, Robert IEEE Department of Measurement and Instrumentation Faculty of Electrical Engineering Automatics Computer Science and Electronics AGH University of Science and Technology 30-059 Cracow Poland

Modern X-ray imaging systems require low noise high-count-rate multichannel front-end electronics. Such systems widely use charge-sensitive amplifiers (CSA) with pole-zero cancellation (PZC) circuits for sensor readout. CSAs in multichannel ASICs often include continuous reset systems based on MOS transistors discharging the integrating capacitance. Noise requirements for such front-end electronics put the effective CSA feedback resistance in the range of hundreds of MΩ. On the other hand, the high input pulse rate generates a dc voltage shift at the CSA output that modifies the CSA feedback resistance and degrades the PZC circuit performance. In the paper we analyze these problems and propose a novel circuit solution to bias transistors in the CSA feedback and in the PZC circuit. This bias circuit tracks the above mentioned voltage shift at the CSA output and ensures proper cancellation of the CSA feedback pole even in the case of high rates of input pulses. We present measurements of a test structure for the continuous CSA feedback discharge and implementation of this circuit in a fast multichannel ASIC manufactured in the 0.35 μm CMOS technology. The circuit performance for the high input pulse rate is described in detail. © 2008 IEEE.

关键词： Amplifiers (electronic)

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Biotelemetry

引用

作者： Cerny, Martin Penhaker, M. Department of Measuring and Control Faculty of Electrical Engineering and Computer Science VSB - Technical University of Ostrava Ostrava Czech Republic

ISBN: (纸本)9783540693666

The biotelemetry is more common application of biomedical engineering and telemetry in our professional life. By this reason the biotelemetry is taught in our bachelor study program Biomedical technology from its beginning. These lessons are focused on the basics of networks, wired communications and wireless communication standards. Students learn systematically grounds of modern telemetry in the application in the biomedical engineering. The paper is focused on system of lectures and system of practical laboratory exercises. © 2008 Springer-Verlag.

关键词： Biomedical engineering

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The influence of the Cole-Cole model coefficients on the parameters of the recovery voltage phenomena of paper-oil insulation

The influence of the Cole-Cole model coefficients on the par...

引用

2008 IEEE International Conference on Dielectric Liquids, ICDL 2008

作者： Wolny, S. Zdanowski, M. Opole University of Technology Faculty of Electrical Engineering Automatic Control and Computer Science Department of Electrical Power Engineering Prószkowska 76 B2 45-748 Opole Poland

ISBN: (纸本)1424415853

The paper presents the application of the Cole-Cole model for determining the runs of the return voltage of the paper-oil insulation sample through a computer simulation. Different insulation conditions were simulated through an adequate selection of parameters α and τ of the Cole-Cole model. For calculation purposes, a series - parallel substitute scheme, obtained through approximation of a discrete characteristic operator impedance Za of the model applied, was used. The diagnostics of the simulated insulation condition was based on the analysis of a few selected parameters of the return voltage, obtained from time characteristics.

关键词： Insulation

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